Exeter Flood Defence Scheme
Exeter, Devon, UK (along the River Exe, from Cowley Bridge to Bridge Road, Countess Wear) · Upgrades between 2014 and 2023 (Phase 1: 2014-2016; Phase 2: 2016-2021; minor upgrades 2021-2023) · £30 million (total cost, with £6 million from government growth funding, £3 million each from Exeter City Council and Devon County Council, remainder from flood defence grant in aid)
The judgement call
Account-gated at launchThe scheme was initiated due to studies indicating existing defences would not protect vulnerable parts of the city in more extreme floods. - The project demonstrates a multi-phased approach, with Phase 1 focusing on immediate risk reduction and Phase 2 on broader city-wide protection. - Significant partnership funding from various government and local entities. - Emphasis on environmental enhancements alongside flood protection, including fish passes and wetland creation. - The Exwick Radial gates automatically divert excess water, showcasing adaptive management.
Key engineering challenges
Upgrading existing flood defences (originally built in the 1960s-70s) to protect against more extreme flood events. - Deepening the Trews flood relief channel and lowering its side spill weir to increase flow capacity. - Constructing new flood walls, flood gates, control structures, and bespoke demountable defences within an urban environment. - Mitigating environmental impact through habitat creation (wetlands, tree planting) and biodiversity improvements.
Project facts
- Client / owner
- Environment Agency; Exeter City Council; Devon County Council
- Lead contractor
- —
- Lead designers
- —
- Project type
- upgrade | refurbishment
- Scale
- Reduces flood risk to more than 3,000 homes and businesses; spans over eight kilometres along the River Exe; increased system capacity from 700m³/s to nearly 900m³/s; includes raised embankments and walls, 14 flood gates, demountable barriers, and control structures; two fish passes built.
- Disciplines
- civil; hydraulic; environmental; geotechnical
- Standards & frameworks
- Designed to raise protection standard from 1-in-40 year to 1-in-80 year flood event (with a goal of less than 1% chance in any given year).
Sources: "Exeter flood defence scheme", GOV.UK, 2022, https://www.gov.uk/government/publications/exeter-flood-defence-scheme/exeter-flood-defence-scheme - "Exeter braces for winter floods as defences upgrade and warning systems enhance", What's On In Exeter, 2025, https://www.whatsoninexeter.com/exeter-braces-for-winter-floods-as-defences-upgrade-and-warning-systems-enhance/ - "Ecology mitigation works, Exeter flood defence scheme", Thomson Environmental Consultants, https://www.thomsonec.com/projects/ecology-mitigation-works-exeter-flood-defence-scheme/ - "Cowley Bridge Jn – Demountable Flood Defence", The PWI, https://www.thepwi.org/wp-content/uploads/2021/05/21-April-12-Drainage-at-Cowley-Bridge-Junction-Exeter-Mark-Howells.pdf